1. Field of the Invention
The present invention relates to a method of manufacturing a cigarette which suppresses a spread of burn and an apparatus for manufacturing a cigarette which suppresses a spread of burn.
2. Description of the Related Art
A cigarette which suppresses a spread of burn is a cigarette structured such that, if it is left not to be smoked after it is lighted, the lighted cigarette ceases to burn, or a cigarette structured such that, if it is erroneously dropped onto a combustible material while the cigarette is left not to be smoked after it is lighted and the lighted cigarette continues to burn, the heat of the burning cigarette is spread into the the combustible material and the burning cigarette case to burn before it burns the combustible material. The cigarette which suppresses the spread of burn has been well known by, for example, Japanese Patent No. 2783803.
In the burn spread suppressing cigarette, which is disclosed in the Japanese Patent specification described above, burn control agent is coated on a tobacco wrapping paper sheet at a plurality of annular regions positioned apart from each other by a predetermined distance in a longitudinal direction of the cigarette. If the burn spread suppressing cigarette is left not to be smoked after an end of the cigarette to be lighted is lighted, the burn of the cigarette is extinguished when the burn of the cigarette reaches the annular region of the burn control agent. On the other hand, if the cigarette is smoked continuously after it is lighted, the burn of the cigarette is not extinguished by the burn control agent even when the burn reaches the annular region of the burn control agent.
In the conventional burn spread suppressing cigarette which is structured as described above, an ordinary burn like in an ordinary cigarette is maintained between the adjacent annular regions of the burn control agent. Therefore, if the conventional burn spread suppressing cigarette is erroneously left on a combustible material and burns ordinarily between the adjacent annular regions of the burn control agent, it does not burn the combustible material but it severely scorches the combustible material depending on a kind of the combustible material, before the burn reaches the annular region of the burn control agent and is extinguished by the burn control agent.
This invention is derived from above described circumstances, an object of the present invention is to provide a method of manufacturing a cigarette which suppresses a spread of burn and an apparatus for manufacturing a cigarette which suppresses a spread of burn, in the cigarette manufactured by this method or this apparatus, when the lighted cigarette is erroneously left on a combustible material, burn of the cigarette is cased, heat of the burning cigarette is spread into a combustible material and does not only burn but also scorch the combustible material, or even if the heat of the burn scorches the combustible material the scorch does not become more severe than in the past.